/*
 * FreeRTOS V202212.00
 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * https://www.FreeRTOS.org
 * https://github.com/FreeRTOS
 *
 */

/******************************************************************************
 * This project provides two demo applications.  A simple blinky style project,
 * and a more comprehensive test and demo application.  The
 * mainCREATE_SIMPLE_BLINKY_DEMO_ONLY setting (defined in this file) is used to
 * select between the two.  The simply blinky demo is implemented and described
 * in main_blinky.c.  The more comprehensive test and demo application is
 * implemented and described in main_full.c.
 *
 * This file implements the code that is not demo specific, including the
 * hardware setup and standard FreeRTOS hook functions.
 *
 * When running on the HiFive Rev B hardware:
 * When executing correctly the red LED will toggle every three seconds.  If
 * the red LED toggles every 500ms then one of the self-monitoring test tasks
 * discovered a potential issue.  If the red led stops toggling then a hardware
 * exception occurred or an assert was hit.
 *
 * ENSURE TO READ THE DOCUMENTATION PAGE FOR THIS PORT AND DEMO APPLICATION ON
 * THE http://www.FreeRTOS.org WEB SITE FOR FULL INFORMATION ON USING THIS DEMO
 * APPLICATION, AND ITS ASSOCIATE FreeRTOS ARCHITECTURE PORT!
 *
 */

/* FreeRTOS kernel includes. */
#include <FreeRTOS.h>
#include <task.h>

/* Standard includes. */
#include <stdio.h>

/* Set mainCREATE_SIMPLE_BLINKY_DEMO_ONLY to one to run the simple blinky demo,
or 0 to run the more comprehensive test and demo application. */
#define mainCREATE_SIMPLE_BLINKY_DEMO_ONLY  0

/* Set to 1 to use direct mode and set to 0 to use vectored mode.
 *
 * VECTOR MODE=Direct --> all traps into machine mode cause the pc to be set to the
 * vector base address (BASE) in the mtvec register.
 *
 * VECTOR MODE=Vectored --> all synchronous exceptions into machine mode cause the
 * pc to be set to the BASE, whereas interrupts cause the pc to be set to the
 * address BASE plus four times the interrupt cause number.
*/
#define mainVECTOR_MODE_DIRECT              0

/* UART hardware constants. */
#define mainUART_BASE_ADDRESS               ( *( volatile uint32_t * ) 0x20000000UL )
#define mainUART_TX_DATA                    0x00
#define mainUART_TX_CTRL                    0x08
#define mainUART_RX_CTRL                    0x0c
#define mainUART_CLOCK_DIV                  0x18
#define mainUART_TX_ENABLE_BIT              (1UL <<  0UL)
#define mainUART_RX_ENABLE_BIT              (1UL <<  0UL)
#define mainUART_TX_FULL_BIT                (1UL << 31UL)
#define mainUART_REGISTER( offset )         ( ( mainUART_BASE_ADDRESS + offset ) )
#define mainUART_REGISTER_WORD( offset )    ( *( ( uint32_t * ) mainUART_REGISTER( offset ) ) )

/* Hardware LED specifics. */
#define mainRED_LED_PIN                     ( 1UL << 0x16UL )
#define mainLED_IO_BASE_ADDRESS             ( 0x10012000UL )
#define mainRED_LED_INPUT_ENABLE_REG        ( * ( uint32_t * ) ( mainLED_IO_BASE_ADDRESS + 4UL ) )
#define mainRED_LED_OUTPUT_ENABLE_REG       ( * ( uint32_t * ) ( mainLED_IO_BASE_ADDRESS + 8UL ) )

/* Hardware LED specifics. */
#define mainUART_PINMUX_BASE_ADDRESS        ( 0x10012000 )
#define mainUART0_BASE_ADDRESS              0x10013000UL
#define mainUART_CLOCK_RATE                 16000000UL
#define mainUART_BAUD_RATE                  115200UL
#define mainUART0_TX_DATA_REG               ( * ( uint32_t * ) ( mainUART0_BASE_ADDRESS + 0UL ) )
#define mainUART0_TX_DATA_BYTE_REG          ( * ( uint8_t * ) ( mainUART0_BASE_ADDRESS + 0UL ) )
#define mainUART0_DIV_REG                   ( * ( uint32_t * ) ( mainUART0_BASE_ADDRESS + 24UL ) )
#define mainUART0_TXCTRL_REG                ( * ( uint32_t * ) ( mainUART0_BASE_ADDRESS + 8UL ) )
#define mainUART0_RXCTRL_REG                ( * ( uint32_t * ) ( mainUART0_BASE_ADDRESS + 12UL ) )
#define mainUART0_GPIO_SEL_REG              ( * ( uint32_t * ) ( mainUART_PINMUX_BASE_ADDRESS + 60UL ) )
#define mainUART0_GPIO_SEL_EN               ( * ( uint32_t * ) ( mainUART_PINMUX_BASE_ADDRESS + 56UL ) )
#define mainUART_TXEN_BIT                   ( 1UL )
#define mainUART0_PIN                       ( 0x30000UL )

/* Registers used to initialise the PLIC. */
#define mainPLIC_PENDING_0                  ( * ( ( volatile uint32_t * ) 0x0C001000UL ) )
#define mainPLIC_PENDING_1                  ( * ( ( volatile uint32_t * ) 0x0C001004UL ) )
#define mainPLIC_ENABLE_0                   ( * ( ( volatile uint32_t * ) 0x0C002000UL ) )
#define mainPLIC_ENABLE_1                   ( * ( ( volatile uint32_t * ) 0x0C002004UL ) )

/*-----------------------------------------------------------*/

extern void freertos_risc_v_trap_handler( void );
extern void freertos_vector_table( void );

/*
 * main_blinky() is used when mainCREATE_SIMPLE_BLINKY_DEMO_ONLY is set to 1.
 * main_full() is used when mainCREATE_SIMPLE_BLINKY_DEMO_ONLY is set to 0.
 */
#if mainCREATE_SIMPLE_BLINKY_DEMO_ONLY == 1
    extern void main_blinky( void );
#else
    extern void main_full( void );
#endif /* #if mainCREATE_SIMPLE_BLINKY_DEMO_ONLY == 1 */

/*
 * Prototypes for the standard FreeRTOS callback/hook functions implemented
 * within this file.  See https://www.freertos.org/a00016.html
 */
void vApplicationMallocFailedHook( void );
void vApplicationIdleHook( void );
void vApplicationStackOverflowHook( TaskHandle_t pxTask, char *pcTaskName );
void vApplicationTickHook( void );

/*
 * Setup the hardware to run this demo.
 */
static void prvSetupHardware( void );

/* Simple polling UART send function. */
void vSendString( const char * const pcString );

/* Toggle the red LED. */
void vTogglelED( void );

/*-----------------------------------------------------------*/

int main( void )
{
    prvSetupHardware();

    /* The mainCREATE_SIMPLE_BLINKY_DEMO_ONLY setting is described at the top
     * of this file. */
    #if( mainCREATE_SIMPLE_BLINKY_DEMO_ONLY == 1 )
    {
        main_blinky();
    }
    #else
    {
        main_full();
    }
    #endif
}
/*-----------------------------------------------------------*/

static void prvSetupHardware( void )
{
    /* Set all interrupt enable bits to 0. */
    mainPLIC_ENABLE_0 = 0UL;
    mainPLIC_ENABLE_1 = 0UL;

    /* Clear all pending interrupts. */
    mainPLIC_PENDING_0 = 0UL;
    mainPLIC_PENDING_1 = 0UL;

    /* Disable Red LED input. */
    mainRED_LED_INPUT_ENABLE_REG &= ~mainRED_LED_PIN;

    /* Enable Red LED output. */
    mainRED_LED_OUTPUT_ENABLE_REG |= mainRED_LED_PIN;

    /* Set UART baud rate. */
    mainUART0_DIV_REG = ( mainUART_CLOCK_RATE / mainUART_BAUD_RATE ) - 1;

    /* Enable UART Tx. */
    mainUART0_TXCTRL_REG |= mainUART_TXEN_BIT;
    mainUART0_GPIO_SEL_REG &= mainUART0_PIN;
    mainUART0_GPIO_SEL_EN |= mainUART0_PIN;

    #if( mainVECTOR_MODE_DIRECT == 1 )
    {
        __asm__ volatile( "csrw mtvec, %0" :: "r"( freertos_risc_v_trap_handler ) );
    }
    #else
    {
        __asm__ volatile( "csrw mtvec, %0" :: "r"( ( uintptr_t )freertos_vector_table | 0x1 ) );
    }
    #endif
}
/*-----------------------------------------------------------*/

void vToggleLED( void )
{
static uint32_t ulLEDState = 0;

    if( ulLEDState == 0 )
    {
        mainRED_LED_OUTPUT_ENABLE_REG |= mainRED_LED_PIN;
    }
    else
    {
        mainRED_LED_OUTPUT_ENABLE_REG &= ~mainRED_LED_PIN;
    }
    ulLEDState = !ulLEDState;
}
/*-----------------------------------------------------------*/

void vSendString( const char * const pcString )
{
uint32_t ulIndex = 0;

    /* Crude polling UART Tx. */
    while( pcString[ ulIndex ] != 0x00 )
    {
        while( ( mainUART0_TX_DATA_REG & mainUART_TX_FULL_BIT ) != 0UL );
        mainUART0_TX_DATA_BYTE_REG = pcString[ ulIndex ];
        ulIndex++;
    }
}
/*-----------------------------------------------------------*/

void vApplicationMallocFailedHook( void )
{
    /* vApplicationMallocFailedHook() will only be called if
     * configUSE_MALLOC_FAILED_HOOK is set to 1 in FreeRTOSConfig.h.  It is a hook
     * function that will get called if a call to pvPortMalloc() fails.
     * pvPortMalloc() is called internally by the kernel whenever a task, queue,
     * timer or semaphore is created.  It is also called by various parts of the
     * demo application.  If heap_1.c or heap_2.c are used, then the size of the
     * heap available to pvPortMalloc() is defined by configTOTAL_HEAP_SIZE in
     * FreeRTOSConfig.h, and the xPortGetFreeHeapSize() API function can be used
     * to query the size of free heap space that remains (although it does not
     * provide information on how the remaining heap might be fragmented). */
    taskDISABLE_INTERRUPTS();
    for( ;; );
}
/*-----------------------------------------------------------*/

void vApplicationIdleHook( void )
{
    /* vApplicationIdleHook() will only be called if configUSE_IDLE_HOOK is set
     * to 1 in FreeRTOSConfig.h.  It will be called on each iteration of the idle
     * task.  It is essential that code added to this hook function never attempts
     * to block in any way (for example, call xQueueReceive() with a block time
     * specified, or call vTaskDelay()).  If the application makes use of the
     * vTaskDelete() API function (as this demo application does) then it is also
     * important that vApplicationIdleHook() is permitted to return to its calling
     * function, because it is the responsibility of the idle task to clean up
     * memory allocated by the kernel to any task that has since been deleted. */
}
/*-----------------------------------------------------------*/

void vApplicationStackOverflowHook( TaskHandle_t pxTask, char *pcTaskName )
{
    ( void ) pcTaskName;
    ( void ) pxTask;

    /* Run time stack overflow checking is performed if
     * configCHECK_FOR_STACK_OVERFLOW is defined to 1 or 2.  This hook
     * function is called if a stack overflow is detected. */
    taskDISABLE_INTERRUPTS();
    for( ;; );
}
/*-----------------------------------------------------------*/

void vApplicationTickHook( void )
{
    /* The tests in the full demo expect some interaction with interrupts. */
    #if( mainCREATE_SIMPLE_BLINKY_DEMO_ONLY != 1 )
    {
        extern void vFullDemoTickHook( void );
        vFullDemoTickHook();
    }
    #endif
}
/*-----------------------------------------------------------*/

void freertos_risc_v_application_interrupt_handler( uint32_t ulMcause )
{
char pcCause[ 20 ];

    /* Not implemented yet! */
    sprintf( pcCause, "%u", ulMcause );
    configPRINT_STRING( pcCause );
    configASSERT( ulMcause == 0 );
}
/*-----------------------------------------------------------*/

void freertos_risc_v_application_exception_handler( uint32_t ulMcause )
{
char pcCause[ 20 ];

    /* Not implemented yet! */
    sprintf( pcCause, "%u", ulMcause );
    configPRINT_STRING( pcCause );
    configASSERT( ulMcause == 0 );
}
/*-----------------------------------------------------------*/

void *malloc( size_t xSize )
{
    /* The linker script does not define a heap so artificially force an assert()
     * if something unexpectedly uses the C library heap.  See
     * https://www.freertos.org/a00111.html for more information. */
    configASSERT( xTaskGetTickCount() == 0x00 );
    return NULL;
}
/*-----------------------------------------------------------*/
